Production of catalyst tablets

ABSTRACT

Production of catalyst tablets by admixing the catalyst particles, with or without substrate, with graphite and a polyethylene, polyproplene, polyethylene glycol and/or polypropylene glycol; and then tabletizing the mass.

United States Patent 91 Rottig et al.

PRODUCTION OF CATALYST TABLETS Inventors: Walter Rottig,

Oberhausen-Sterkrade-Nord; Hans-Heinrich Saenger, Mulheim/Ruhr-Speldorf, both of Germany Ruhrchemie Aktiengesellschaft, Oberhausen-l-lolten, Germany Filed: Jan. 20, 1972 Appl. No.: 219,495

Related U.S. Application Data Continuation-impart of Ser. No. 714,781, March 21, l968, abandoned.

Assignee:

Foreign Application Priority Data Apr. l, 1967 Germany r. R 45649 U.S. Cl 252/428, 252/430, 252/477 R, 252/29, 252/473 Int. Cl.... B0lj 11/06, ClOm 7/04, ClOm 7/14, ClOm 7/26 Aug. 28, 1973 OTHER PUBLICATIONS Little et al., Tablet Making, 2nd Edition 1963), Pages 63 & 64, Published by Maiden Printing, 137-141 Vauxhall Rd, Liverpool 3, England Primary Examiner-Patrick P. Garvin Attorney-Ralph D. Dinklage and Arnold Sprung et al.

[57] ABSTRACT Production of catalyst tablets by admixing the catalyst particles, with or without substrate, with graphite and a polyethylene, polyproplene, polyethylene glycol and- /or polypropylene glycol; andv then tabletizing the mass.

7 Claims, No Drawings PRODUCTION OF CATALYST TABLETS This is a continuation in part of application Ser. No. 714,781 filed March 21, 1968, now abandoned.

This invention relates to the forming of catalyst tablets. It more particularly refers to an improved technique for producing tablet form catalysts.

Tablet form catalysts are well known. These materials have been known to be produced in various sizes as required for the particular process in which such will be used. The preparation of catalysts in tablet-form in an appropriate single or two-stage performing press is known in the art (see Ullmann Encyklopaedie der technischen Chemie, Vol. 9, 1957, page 275). Depending. upon the intended'use of the catalyst tablets, their size may be 5 X 5 mm, but'may'alsobe larger or smaller. Generally, the catalyst mass to'be tabletted is fed into the performingpress in finely divided form, as for instance as powder. Since the flowability of' such powders is not always satisfactory and the catalyst tablets formed thereof do not always possess adequate'cohesiveness andrigidity, the catalyst powder is then admixed with additives to improve these conditions. These additives include for instance graphite in its diffcrent modifications, or stearic acid or stearates, such as magnesium or aluminium stearate. Theamounts and ratios of the additives depend upon the'particular catalyst'powder and may vary widely. it is knownto use a single additive component or mixtures of several components as the need'requires.

Catalyst tablets prepared in'this manner are normally not pre-activated nor' pre-reducedandrequire convenient treatment after pelletization'in order to attain'optimal activity. This treatment can be performed within or outside of the vessel in which the catalyst is intended to be used.

Use of so-called stabilized catalysts has been increasing for some time. ln this regard, ithas become desirable to subject the catalyst to a reducing-ftreatment, for instance with'hydrogen, as wellas to'subsequently stabilize such catalyst in suitable shape, as for instance in form of tablets, string-shaped=particles or powder. If desired, the thus prereduced catalyst-maybe used for the production of stabilized. catalystta-blets. Another embodiment-of the. preparation proceeds from preformed catalyst, as for instance from'tablet's or string-shaped granules. This is'especially the case. if precipitated catalysts are used. These catalysts-may, if desired, be prepared together with-a: substrate of carrier materials as for instance diatomaceous earth, Aerosil, or other Al O and'lor SiO- containing cornpounds. Such. catalyst" compositions often suffer' from greater or lesser shrinkage duringzreductionand stabili=- zation thereof which-shrinkage impairsthemechanical properties thereof. It iseven possiblethat those' catalysts can; become unservicable, especiall'yfo'r fixed-bedprocesses, because; of such shrinkage. it is' therefore stices by movable rams whereby to produce tablets with good mechanical properties. The movable parts of such devices generally have a significantly long opera of a given molding device. In some cases the number of good pellets produced is extremely small.

It is therefore an object of this invention to provide a novel production means for producing catalyst tablets and/or pellets.

It is another object of this invention to provide a novel composition suitable for pelletizing or tabletiz- It is a further object of this invention to provide a novel composition catalyst pellet-or tablet.

Other and additional objects will become apparent from a consideration of this entire specification including the claims hereof.

In accord with and fulfilling these objects, one aspect ofthis'invention resides in a catalyst composition comprising a catalyst, graphite and an ethylene and/or propylene homo or copolymer, or an ethylene and/or propylene glycol homo or copolymeric compound having a molecular weight of about 3,00010 2,000,000 and a meltingpoint of about 40 to C. Accordin g to this invention, the composition is suitably particulate in nature with the polymer portion thereof having a particle size range of about 1 to 1,000 microns.

Preferably about 1 to 4 percent graphite and about 0.3 to 1 percent of the polymeric compound, related to the entire composition weight, are added. Although the total amount of' graphite and polymeric compounds may be greater than 5 percent, such is not considered essential or particularly desirable, since no substantial additional effectis thereby obtained. Graphite is used in its known commercially available form having a caron content of more than 99 percent and a grain-size distribution such that the amount of particles up to 10 microns amounts to about 50 percent.

Ad vantageously the molecular weight of the added polyolefins ranges between about 10,000 and 100,000; that of the added polyalkyleneglycols is between about 5,000 and20,000. The melting point of the polymeric compoundsis preferably about 50 to 150.

The polymeric compounds are preferably used in as finely'divided condition'as possible in order to assure a homogenous mixture thereof with the other components. It has been observed that particularly advantageousresults are obtained when polymeric compounds with a'grain-size distribution spectrum containing not more than at most 1 percent particles of more than 1 ,000 u-and'at'most l0 percent particles of more than 500 rare'usedi The polymers are generally available in the desired size from conventional production; coarser grained materials'must' be reduced to the desired grain size distribution in conventional grindingor'cominuting devices known inthe' art.

With the process according to the invention it has been made possible to increase the operational life of the molding means, or matrices, by more than ten-fold.

It is suggested that the particular nature of the catastring-shaped particles so obtained were reduced at a temperature of about500 with a hydrogen stream, subsequently' stabilized in a known manner, comminuted and separated by sieving so that after sieving no lytic, and possibly the substrate, material employed is 5 particles of more than 1.5 mm remained. not critical to the invention hereof. Substantially any 1.5 percent by weight graphite and 0.5 percent b catalyst can be used as desired. It may be well to conweight magnesium stearate were'added to the product sider that catalysts and/or substrates which have been obtained as hereinbefore described and intimately adpelletized and/or tabletized in the past by art recogmixed therewith in a mixing device. The admixture was nized procedures are suited to use in this invention. Exmoulded into tablets, having a diameter of 5 mm and emplary of these known catalysts are nickel, cobalt, also a length of 5 mm in a conventional laboratory preiron, other metals of the platinum group as well as copforming press. After a total tablet output of 3.3 kg per per, silver and chromium. mold cavity, the rate of objectionable and/or partly In the following Examples the tabletting machine damaged tablets increased rapidly. Atasubsequent inwhich was used was conventional, commercially availl5 spection of the matrices used, marked stressable equipment. It consisted of a vertically disposed, appearances were observed, which made the further exchangeable cylinrical body of stainless steel. Several production of unobjectionable tablets difficult if not mold cavities were disposed in the stainless steel body, impossible. Instead of the above noted addition of 0.5 each of which had two stainless steel ram rods operapercent by weight magnesium stearate, the same tively associated therein, and means to drive the ram amount of polythyleneglycol, having a molecular rods toward each other within the mold cavities. The weight of about 10,000 was added to an amount of catinside diameter of the mold cavities and the outside dialyst as set forth above. The output of tablets was inameter of the ram rods, less clearance of course, correcreased to more than 50 kg per mold cavity. With a spond to the outside diameter of the tablets being propolyethyleneglycol having a molecular weight of about duced. The tablet height is determined by the cumula- 20,000 a substantially identical improved output was tive throw of the ram rods and the clearance left there b i d, with a polyethyleneglycol having a molecubetweenlar weight of 5,000 the output per mold cavity was im- AS noted above, conventional tablet making p proved over the magnesium stearate but was slightly tions in q ipm n f h yp have been found to be reduced as compared with the'higher molecular weight less than satisfactory because after some given period of l h l l l products of time, tablets obtained from a give" mold cavity are In another example of this invention, 0.5 percent by no longer satisfactory. This shows up in produced tabi h f polyethylene having a molecular weight f lets which have unsatisfactory cohesiveness and rigidabout 0 000 obtained by the 11 Zi l ity, or in tablets in which the catalyst powder is insuffi- Synthesis in the f f a fi powder w added to ciemly compacted; The gffectlveness lupricams the catalyst composition hereinbefore mentioned inaddec'l to a catalyst composmon for tablimng f' stead of polyethyleneglycol, an output per mold cavity a'ted terms of l Q y taplets of a El compos" was obtained at the susequent tabletting procedure, 9" and g'ven {mmmum phys' cal propemes can be which surmounted that obtained with magnesium steatalned from a single mold cavity (or stemple). The val- 40 rate by more than twentyfold. ues expressed hereinafter are average values taken Further tests were performed as follows: from multiple mold cavities in a single machine.

In the following tests, those carried out at room tem- A composmon w prepared as forth on page 7 perature were at a pressure of 13 except that 1.5 weight percent graphite used as the The following example is illustrative of this invention only lubncam' The result was producuon of kllo without being limiting thereof. grams of tablets per mold cavity.

a A composition as set forth immediately above but re- EXAMPLE placing the graphite with 0.5 weight percent polyethyl- String-shaped catalyst grains, containing about 37 ene of 60,000 molecular weight resulted in a producpercent nickel, about 3 percent magnesium oxide and tion of 3.7 kg of tablets per mold cavity.

TABLE Test number l 2 .5 4 'l n 7 a 'l 10 1 12 Graphite"... Mg-stearate Polyethylene Polypropylene Polyethyleneglycol 0 Output 2.7 3.3

about 24 percent diatomaceous earth, with the remainder being water, carbon dioxide in form of carbonate etc., were prepared by precipitating nickel nitrate. as well as magnesium nitrate (the latter serving as activator) from a solution thereof with a sodium carbonate solution (both solutions having a temperature of about 100") in the presence of diatomaceous earth. The precipitate was filtered, washed, dried and molded. The

A composition as set forth immediately above, but replacing the graphite with polypropylene of a molecular weight of 50,000, resulted in a production of 3.9 kilograms of tablets per mold cavity.

A composition as set forth immediately above, but replacing the graphite with polyethylene glycol of a molecular weight of 5,000, resulted in a production of 4.5 kilograms of tablets per mold cavity.

A composition as set forth immediately above, but utilizing 0.5 weight percent polypropylene ofa molecular weight of 50,000 in addition to the graphite, resulted in a production of 50 kilograms of tablets per mold cavity.

Additional tabletting compositions were prepared and tested with different proportions of lubricant therein. The following table sets forth the various lubricants, proportions and outputs which have been found. Proportions reported are in weight percent and output is in kilograms per mold cavity.

What is claimed is:

l. A composition comprising a pelletizable catalyst, about 0.5 to 4 weight percent graphite and about 0.1 to 1 weight percent of a homopolymer of ethylene, propylene, ethylene glycol, propylene glycol, a copolymer of ethylene and propylene or a copolymer of ethylene glycol and propylene glycol having a molecular eight of about 3,000 to 2,000,000 and a melting point of about 40 to 150C.

2. Composition claimed in claim 1 wherein said graphite proportion is about 1 to 4 weight percent and said polymer proportion is about 0.3 to 1 weight percent. I

3. Composition claimed in claim 1 wherein said polymer has a melting point of about 50 to C; said glycol polymer has a molecular weight of about 5,000 to 20,000; and said other polymer has a molecular weight of about 10,000 to 100,000.

4. Composition claimed in claim 1 in tablet form.

5. Composition claimed in claim 1 in finely divided admixture form wherin said polymer particle size is about 1 to 1,000 microns.

6. Composition claimed in claim 5, wherein up to about 1 percent of said polymer particles are larger than 1,000 microns and up to about 10 percent of said polymer particles are larger than 500 microns.

7. A composition claimed in claim 1, wherein the catalyst portion of said composition has been reduced prior to tableting.

I. t i t I E U NITE D' OFFICE jCERTIFICA E CORR EC'IIZON I 'paten n- 3,755,*19.2 st'ed A gu 28,- 1975 Inirentoifs) Walter Rottihg and Dr. Hens Heinrich S aenger It is certified that errors ajioears in the aboire -identified patent and that said Letters Patent are hereby corrected as shown below:

Column line-2O "polythyleneglyool" should be j-- polyethyleneglycol Columns 3 and A the Table v The table should be inserted at columns 5 and-6 before the claims. I

Signed and sealed this ,lst day of October 197 (SEAL) Attestz' v MCCOY M. GIBSON, JR. c. MARSHALL DANN Attesting Officer I Commissioner of Patents F ORM PO-IOSO (IO-69) uscoMM-oc sows-Pea UYS GOVERNMENY PRINTING OFFICE; o 

2. Composition claimed in claim 1 wherein said graphite proportion is about 1 to 4 weight percent and said polymer proportion is about 0.3 to 1 weight percent.
 3. Composition claimed in claim 1 wherein said polymer has a melting point of about 50* to 150*C; said glycol polymer has a molecular weight of about 5,000 to 20,000; and said other polymer has a molecular weight of about 10,000 to 100,000.
 4. Composition claimed in claim 1 in tablet form.
 5. Composition claimed in claim 1 in finely divided admixture form wherin said polymer particle size is about 1 to 1,000 microns.
 6. Composition claimed in claim 5, wherein up to about 1 percent of said polymer particles are larger than 1,000 microns and up to about 10 percent of said polymer particles are larger than 500 microns.
 7. A composition claimed in claim 1, wherein the catalyst portion of said composition has been reduced prior to tAbleting. 